Front Flip Animation Messed Up Due To Quaternion
Switch to pose mode and find and select the bone that rotates backwards. Go to the last keyframe in your animation (frame 80 it looks like), and negate the W, X, Y, Z of the rotation in the Bone Properties panel, ie. replace 0.1 with -0.1. Insert a keyframe to save the values. Your rotation should now work.
(I think there's an op that will do this automatically but I can't remember what it is...)